1. Field of the Invention
The present invention relates to a jetting timing determining method for determining a timing at which a liquid such as an ink is jetted from a liquid-droplet jetting head such as an ink-jet head, a liquid-droplet jetting method, and an ink-jet printer which jets the ink at a predetermined timing.
2. Description of the Related Art
An example of a technique to utilize an ink-jet head, in which a plurality of nozzles for jetting (discharging) an ink is formed, is described in Japanese Patent Application Laid-open No. 2005-271543.
When the ink is jetted from an ink-jet head as described in Japanese Patent Application Laid-open No. 2005-271543, a difference sometimes arises in ink-jetting characteristics between a case in which the ink is jetted singly or independently from one nozzle (hereinafter referred to as “single jetting” or “independent jetting”) within one printing cycle and a case in which the ink is jetted from a plurality of nozzles concurrently (hereinafter referred to as “concurrent jetting”) within one printing cycle. For example, jetting speeds at which the ink is concurrently jetted from the nozzles respectively in the concurrent jetting is greatly smaller than the jetting speed in the single jetting in some cases. This makes the variation in the ink jetting speeds to be greater in the concurrent jetting than that in the single jetting. In the concurrent jetting, the ink is jetted concurrently within a period of time (about 0.5 microseconds) having duration to an extent that concentration of an electric power consumption can be avoided.
As a cause to generate, more in the concurrent jetting than in the single jetting, such a variation in the jetting characteristics, there is a phenomenon called “cross talk”. The cross talk is a phenomenon in which the vibration or the like, generated in the ink-jet head when the ink is jetted from a certain nozzle, affects or influences the ink jetting from another nozzle different from the certain nozzle. When the ink jetting characteristics are varied among the nozzles upon the concurrent jetting due to the cross talk, there is a fear that an image, formed by the ink jetting, becomes non-uniform. Namely, the reproducibility of the printed image by the ink-jet head is lowered.